A reverse power supply technology is a technology named in a relative manner. A manner in which a switch supplies power to a network terminal and a current flows from the switch to the network terminal is usually referred to as forward power supply. A power supply manner in which the network terminal supplies power to the switch and a current flows from the terminal to the switch is referred to as reverse power supply.
In the prior art, in a fiber to the distribution point (FTTdp for short) network environment, because it is difficult for a distribution point (DP) to obtain power locally, supplying power to the DP becomes a main technical difficulty. One of the solutions is to supply power to the DP by using reverse powering equipment (RPE) in a user's home. Because a conventional twisted pair cabling mode in a home is tandem connection, if reverse power supply is connected to a point, a voltage is not only transmitted to the FTTdp but also transmitted to another point of interface of a line in the home. Conventionally, the other point of interface is generally a terminal device such as a phone. If the voltage is transmitted thereto in a case in which the user is not informed, some terminal devices such as a phone may be burnt.